Refrigerators, freezers and ovens used in the food industry typically include a plurality of rectangular walls joined along adjacent edges. Each wall typically includes an outer panel, an inner panel, and an insulation material between them. The outer and inner panels may be formed of steel, stainless steel, another suitable metal, or another suitable material.
The joints between the adjacent walls are typically filled with caulk to prevent moisture from entering the joints. Sometimes, the joints are also covered with batten strips. When the internal temperature is lowered, the inner wall panels contract relative to the outer wall panels. When the internal temperature is raised, the inner wall panels expand relative to the outer wall panels.
Over time, the contraction and expansion of the inner wall panels causes some of the caulk to fracture and/or work its way out of the joints. Failure of the caulk seams allows moisture to enter the joints. Once inside the joints, the moisture freezes, thaws, expands and contracts, causing further failure of the seams. While the batten strips slow the entry of moisture into the joints, they also make it difficult for moisture already in the joints to escape. Bacteria may also enter the moisture-laden joints and may propagate over time.
One way to prevent moisture from entering the joints is to weld adjacent wall panels together. However, this technique is relatively expensive, and requires the use of specific expansion joints that permit the wall panels to expand and contract without fracturing the joints due to localized stresses.
There is a need or desire for an environmentally-controlled food container having relatively inexpensive seams which do not fracture or otherwise fail due to repeated thermal contraction and expansion of the inner wall panels.